Influence of ¹⁸F-FDG PET/CT on clinical management and outcome in patients with advanced melanoma not primarily selected for surgery based on a linked evidence approach

Purpose: To evaluate the clinical benefit of positron emission tomography (PET)/computed tomography (CT) in patients with advanced melanoma, primarily not selected for surgery based on management changes and survival data using the linked evidence approach (LEA).

Methods: A total of 201 ¹⁸F-FDG PET/CT examinations (n = 33, stage III and n = 168, stage IV) in 119 melanoma patients, primarily not scheduled for surgery, were analysed regarding their impact on clinical management. Patients were selected from a prospective oncological PET/CT registry. The three PET/CT indication groups included unclear lesions in conventional imaging (n = 8), routine follow-up after multiple surgeries (n = 115) and therapy response evaluation of systemic therapy (n = 78). PET/CT-induced management changes were categorized either as major (change from follow-up to surgical or systemic treatment or vice versa, change from surgery to systemic therapy or vice versa) or minor (modifications in systemic therapy). The expected benefit of changes was determined via the linked evidence approach (LEA) connecting registry data, outcome data including overall survival and evidence of diagnostic accuracy of PET/CT based on existing literature.

Results: Related to the total study cohort, a change of management after PET/CT was observed in 48% of scans, including 10% minor and 38% major changes. Major changes involved a shift either from follow-up (33/201) or therapy pause (7/201) to systemic therapy, to surgical or other local therapy (26/201) and BSC (2/201). Nine out of 201 cases resulted in treatment pause of systemic therapy. We could confirm the prognostic value of PET/CT-based management by observing a 5-year survival rate more than roughly doubled in patients followed up after tumour exclusion or under local therapy compared with patients under systemic therapy. We could argue for a patient benefit from PET/CT-based management changes using results on accuracy and therapeutic effects from the literature.

Conclusion: The use of PET/CT in advanced melanoma patients, primarily not considered for surgery, resulted in frequent changes of management associated with a relevant expected clinical benefit especially in patients classified by PET/CT as tumour-free or eligible for radical surgery.